DM died before DC's were born and DF has remarried. Step mum has been in the DC's lives since before they were born but they call her by her first name. People find this odd but everyone's happy with it as step mum said from the off she would never replace their nan and that way when the kids ask about their nan in heaven it's easier to just say nan and know who they're talking about.
So, what do your kids call their step nan/grandad? Is it by names or by the title of nan/grandad?